| 摘要 |
PURPOSE:To enhance wafer cooling temperature from the conventional one in low-temperature etching, to make possible to etch the multifilm structure formed by laminating different kinds of material layers by setting a single temperature, and to improve the selectivity for base layer and the selectivity for resist. CONSTITUTION:Mixed gas of O-gas and H-gas, or the gas containing a very small amount of H2O is used as etching gas, and a wafer is cooled down to 0 deg.C or lower. The H2O, which is present in an etching system, is solidified by a readily determined quantity by the relation between the quantity of moisture and the dew point, and it is adhered to the wafer in the form of ice. This ice is deposited on the wall part of pattern side where the vertical incidence of ions is not generated, and it contributes to the accomplishment of anisotropic configuration. As the ice can be removed easily by heating and evacuation, there is no possibility of having particle contamination.
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